The present invention disclosed herein relates to a small nuclear power generator, and more particularly, to a small nuclear power generator which restores steam to water by applying pressure to the inside of a condenser using a pressurizer disposed over the condenser without condensing steam using cooling water.
One example of the base material of the nuclear power generation in the nuclear power plant is uranium (U).
The atomic weights of uranium are 235 and 238, among which the uranium 235 generates an immense amount of energy when the nuclear fission occurs.
This can be understood through the mass energy equivalence principle of Einstein, which explains that when uranium 235 is disintegrated, a bit of mass decreases and the energy corresponding to this diminished mass occurs.
Like this, when mass is changed into energy, a very large amount of energy can be obtained from a very small amount of matter.
Accordingly, when uranium 235 continues the nuclear fission, a very large amount of heat can be obtained, and steam can be produced from the heat and be used to produce electricity.
A power plant which produces electricity like this is called a nuclear power plant, and the nuclear power plant shows superior operation performance compared to a hydraulic power plant and a thermoelectric power plant so far in terms of the economic feasibility, safety and environmental preservation. Also, the nuclear power plant has been settled as an important power generation facility.
In the nuclear power plant, when an emergent leakage accident of radioactive substances which are generated during the nuclear fission process of the nuclear fission matters occurs, a big disaster may occur. Accordingly, the safety of the nuclear power plant is being treated as a top priority task.
For this reason, the main configuration such as a nuclear reactor is located inside a containment building, and water (hereinafter, referred to as ‘first water’) used as a cooling medium and water (hereinafter, referred to as ‘second water’) used as steam are separated and circulated through different paths, which will be described in more detail as follows with reference to FIG. 1.
FIG. 1 is a view illustrating a configuration of a typical nuclear power plant.
As shown in FIG. 1, a Pressurized Water Reactor (PWR) type of nuclear power plant installed in Korea is configured to include a nuclear reactor 2, a pressurizer 4, a steam generator 6, a turbine/generator 7, and a condenser 8. Among these, the nuclear reactor 2, the pressurizer 4, and steam generator 6 are located inside a containment building 1 for safety.
The nuclear reactor 2 heats the first water to high temperature using heat generated through nuclear fission of a nuclear fuel.
In this case, a control rod 3 of the nuclear reactor 2 may be formed of a material sufficiently absorb thermal neutrons, and controls the reaction of the nuclear fuel while being inserted into and withdrawn from a core of the nuclear reactor 1.
The pressurizer 4 maintains the high-pressure state such that the internal temperature of the nuclear reactor 2 in which the nuclear fission continues does not rise (the first water inside the nuclear reactor does not boil), and serves as a surge tank of a coolant (first water). Also, the pressurizer 4 provides an expansion and condensation space for the nuclear reactor coolant during the normal operation, and maintains a uniform pressure to restrain the pressure variation during the transient state.
The steam generator 6 generates steam by heat-exchanging the first water of high-temperature and high-pressure with the second water.
The turbine/generator 7 includes a turbine 7a rotated by steam generated in the steam generator 6 and a generator 7b connected to the axis of the turbine 7a. The axis of the generator 7b rotates together with the axis of the turbine 7a to produce electricity.
The condenser 8 restore steam discharged after producing electricity to the second water by cooling steam through heat-exchange with cooling water (sea water or river water), and sends the second water to the steam generator 6 again.
In regard to the flow of the first water and the second water, the first water passes the nuclear reactor 2 by a coolant pump 5, and passes the lower ends of the pressurizer 4 and the steam generator 6 while circulating clockwise.
Generally, water starts to boil at a temperature of about 100° C., and in order to prevent this, a high pressure is applied through the pressurizer 4. Thus, the first water is not changed into steam, and moves to the steam generator 6.
The first water of high-temperature and high-pressure introduced through the lower inlet of the steam generator 6 along a pipe is separated from the second water inside the steam generator 6, and converts the second water into steam by applying heat to the second water by heat-exchanging.
Thus, in the RWR nuclear power plant, the first water passing the nuclear reactor 2 and having radioactivity is separated from the second water of the steam generator 6, in spite of an accident, the first water having radioactivity can be confined in the containment building for safety.
Meanwhile, steam generated in the steam generator 6 moves to the turbine 7a along the pipe, and operates the generator 7b to produce electrical energy.
Thereafter, steam discharged out of the turbine 7a moves to the condenser 8, and steam inside the condenser 8 is changed into the second water again by a cooling pipe 11 in which cooling water introduced from the outside through a cooling water pump 9 flows. Thus, the second water is again supplied into the steam generator 6 by a main water supply pump 10 and is circulated.
In a related art, when the condenser 8 condenses steam, steam is condensed while passing the cooling pipe 11. Accordingly, a typical nuclear power plant needs a large amount of cooling water, and thus most nuclear power plants need to be installed near sear or river. That is, the installation place is limited, and when the control rod 3 of the nuclear reactor 2, the turbine 7a, and the cooling function fail simultaneously, a big disaster may occur unless measures are prepared.